我目前正在使用OpenCV和PyTesseract从指定的ROI读取图像。这是我经历过的事情:
import pytesseract
import urllib
import math
import cv2
import numpy as np
from unidecode import unidecode
from PIL import Image
def process_image(path=None):
if path != None:
original_image = cv2.imread(path)
original_height, original_width = original_image.shape[:2]
image = cv2.resize(original_image, (640, int(math.floor(original_height*640/original_width))))
cv2.imwrite('./uploads/resized_image.jpg', image)
height, width = image.shape[:2]
else:
return "Terjadi kesalahan, harap hubungi administrator."
print(height)
print(width)
coord = [
[height - 84, 34, height, 624] #Barcode
# [378, 415, 364, 583], #Tanggal Lahir
# [605, 656, 32, 992]
]
result = None
print ("Recognizing...")
for x in coord:
roi = image[x[0]:x[1],x[2]:x[3]]
print(x[0])
print(x[1])
print(x[2])
print(x[3])
gray = cv2.cvtColor(roi,cv2.COLOR_RGB2GRAY)
ret2,th2 = cv2.threshold(gray,128,255,cv2.THRESH_BINARY+cv2.THRESH_OTSU)
dst = cv2.fastNlMeansDenoising(th2,10,10,7)
cv2.imwrite('./uploads/tmp.jpg',dst)
cao = Image.open('./uploads/tmp.jpg')
rec_string = pytesseract.image_to_string(cao,lang='deu')
if result != None:
result += "\n" + rec_string
else:
result = rec_string
print ("the result is {}".format(result))
return result
在这里，您可以看到它得到一个图像，将其调整为一定大小，然后将图像写入名为resized_image.jpg的新图像中。然后，我尝试根据基于高度的坐标创建ROI。看一下坐标数组，您可以看到我正在尝试通过从高-84到高，以及从34到624的宽度获取坐标来获取底部组件。
事实证明，如果值正确，我会打印出“正在确认...”文本。是的，但是图像不会被处理，并且会弹出此错误:
File ./uploads/24-07-2018/aenkjtWIBYuTZsaU.jpg telah diupload
903
640
Recognizing...
819
34
903
624
OpenCV(3.4.1) Error: Assertion failed (!_src.empty()) in fastNlMeansDenoising, file /opt/conda/conda-bld/opencv-suite_1527005194613/work/modules/photo/src/denoising.cpp, line 119
[2018-07-24 13:51:29,900] ERROR in app: Exception on /api/upload [POST]
Traceback (most recent call last):
File "/home/dennydap/anaconda3/lib/python3.6/site-packages/flask/app.py", line 2292, in wsgi_app
response = self.full_dispatch_request()
File "/home/dennydap/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1815, in full_dispatch_request
rv = self.handle_user_exception(e)
File "/home/dennydap/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1718, in handle_user_exception
reraise(exc_type, exc_value, tb)
File "/home/dennydap/anaconda3/lib/python3.6/site-packages/flask/_compat.py", line 35, in reraise
raise value
File "/home/dennydap/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1813, in full_dispatch_request
rv = self.dispatch_request()
File "/home/dennydap/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1799, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/home/dennydap/Projects/flask-ocr/server.py", line 55, in upload_file
rec_string = process_image(path=path)
File "/home/dennydap/Projects/flask-ocr/pre_img.py", line 39, in process_image
dst = cv2.fastNlMeansDenoising(th2,10,10,7)
cv2.error: OpenCV(3.4.1) /opt/conda/conda-bld/opencv-suite_1527005194613/work/modules/photo/src/denoising.cpp:119: error: (-215) !_src.empty() in function fastNlMeansDenoising
OpenCV(3.4.1) /opt/conda/conda-bld/opencv-suite_1527005194613/work/modules/photo/src/denoising.cpp:119: error: (-215) !_src.empty() in function fastNlMeansDenoising
127.0.0.1 - - [24/Jul/2018 13:51:29] "POST /api/upload HTTP/1.1" 500 -
Error on request:
Traceback (most recent call last):
File "/home/dennydap/anaconda3/lib/python3.6/site-packages/werkzeug/serving.py", line 270, in run_wsgi
execute(self.server.app)
File "/home/dennydap/anaconda3/lib/python3.6/site-packages/werkzeug/serving.py", line 258, in execute
application_iter = app(environ, start_response)
File "/home/dennydap/anaconda3/lib/python3.6/site-packages/flask/app.py", line 2309, in __call__
return self.wsgi_app(environ, start_response)
File "/home/dennydap/anaconda3/lib/python3.6/site-packages/flask/app.py", line 2295, in wsgi_app
response = self.handle_exception(e)
File "/home/dennydap/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1748, in handle_exception
return self.finalize_request(handler(e), from_error_handler=True)
File "/home/dennydap/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1831, in finalize_request
response = self.make_response(rv)
File "/home/dennydap/anaconda3/lib/python3.6/site-packages/flask/app.py", line 1957, in make_response
'The view function did not return a valid response. The'
TypeError: The view function did not return a valid response. The function either returned None or ended without a return statement.
如果我使用的是精确数字，而不是高度-84，则不会显示错误。我做错什么了？
最佳答案
事实证明，定义ROI是错误的。我以为是 roi = image [y1:x1，y2:x2] ，但快速搜索后，它是 roi = image [y1:y2，x1:x2] 。应该已经入睡了。
关于python - 在数组中使用计算值时，Python cv2.error:OpenCV(3.4.1)错误:(-215)!_src.empty()在fastNlMeansDenoising函数中，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/51492385/